From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751796AbdGZQle (ORCPT ); Wed, 26 Jul 2017 12:41:34 -0400 Received: from vps0.lunn.ch ([178.209.37.122]:41045 "EHLO vps0.lunn.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751022AbdGZQl3 (ORCPT ); Wed, 26 Jul 2017 12:41:29 -0400 Date: Wed, 26 Jul 2017 18:41:24 +0200 From: Andrew Lunn To: Franklin S Cooper Jr Cc: linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, netdev@vger.kernel.org, linux-can@vger.kernel.org, wg@grandegger.com, mkl@pengutronix.de, robh+dt@kernel.org, quentin.schulz@free-electrons.com, dev.kurt@vandijck-laurijssen.be, sergei.shtylyov@cogentembedded.com, socketcan@hartkopp.net Subject: Re: [PATCH v2 2/4] can: fixed-transceiver: Add documentation for CAN fixed transceiver bindings Message-ID: <20170726164124.GL12049@lunn.ch> References: <20170724230521.1436-1-fcooper@ti.com> <20170724230521.1436-3-fcooper@ti.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170724230521.1436-3-fcooper@ti.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jul 24, 2017 at 06:05:19PM -0500, Franklin S Cooper Jr wrote: > Add documentation to describe usage of the new fixed transceiver binding. > This new binding is applicable for any CAN device therefore it exists as > its own document. > > Signed-off-by: Franklin S Cooper Jr > --- > Version 2: > Tweak commit message working > Tweak wording for properties > Drop unit addressing > Give example if CAN-FD isn't supported > > .../bindings/net/can/fixed-transceiver.txt | 42 ++++++++++++++++++++++ > 1 file changed, 42 insertions(+) > create mode 100644 Documentation/devicetree/bindings/net/can/fixed-transceiver.txt > > diff --git a/Documentation/devicetree/bindings/net/can/fixed-transceiver.txt b/Documentation/devicetree/bindings/net/can/fixed-transceiver.txt > new file mode 100644 > index 0000000..dc7e3eb > --- /dev/null > +++ b/Documentation/devicetree/bindings/net/can/fixed-transceiver.txt > @@ -0,0 +1,42 @@ > +Fixed transceiver Device Tree binding > +------------------------------ > + > +CAN transceiver typically limits the max speed in standard CAN and CAN FD > +modes. Typically these limitations are static and the transceivers themselves > +provide no way to detect this limitation at runtime. For this situation, > +the "fixed-transceiver" node can be used. > + > +Properties: > + > +Optional: > + max-arbitration-speed: a positive non 0 value that determines the max > + speed that CAN can run in non CAN-FD mode or during the > + arbitration phase in CAN-FD mode. Hi Franklin Since this and the next property are optional, it is good to document what happens when they are not in the DT blob. Also document what 0 means. > + > + max-data-speed: a positive non 0 value that determines the max data rate > + that can be used in CAN-FD mode. A value of -1 implies > + CAN-FD is not supported by the transceiver. -1 is ugly. I think it would be better to have a missing max-data-speed property indicate that CAN-FD is not supported. And maybe put 'fd' into the property name. Andrew